1. Field of the Invention
This invention relates to a digital indication type measuring apparatus.
2. Description of the Prior Art
There has heretofore been known a measuring instrument, in which a photoelectric or electromagnetic type encoder is connected to a so-called contact type measuring instrument for measuring a dimension of a workpiece from a displacement value of a spindle, etc. in a micrometer, slide calipers, dial gauge or the like, to thereby digitally indicate the dimension of the workpiece. The measuring instrument of the type described has been utilized in many fields because of its own characteristics of high accuracy and easy reading. Moreover, the morphological characteristics, particularly, one hand controllability greatly contributes to the wide utilization. As a consequence, for a measuring instrument of this type, compact and light-weight design are important design factors.
In general, in contrast to the tendency of miniatuarization of electronic circuit parts and the like, control parts such as a power source switch and a zero clear button need to have predetermined sizes as viewed from human engineering, and are limited in their locations to a considerable extent. For this reason, in the conventional measuring instrument, the limitation in the number of the control parts frequently necessitates lowered funtional effect and controllability, or electronic circuits complicated beyond necessity.
For example, with the digital indication type micrometer, slide calipers and the like, there are such cases where it is desirable that any one of these measuring instruments be connected to an external component for the recording of measured values except when used singly. In such cases, when a switch for data output is to be provided on the main body of the measuring instrument, a space should be secured for disposing a multiplicity of control parts each having a size of a predetermined value or more, whereby the measuring instrument becomes large-sized as a whole, the aforesaid compactness in size cannot be attained, handling is troublesome, and mistaken operations tend to occur. However, if the switch for data output is provided on the external component, then inconvenience occurs in handling. As a consequence, when the expanded functional effect is desired, it is very difficult to satisfy both requirements of compactness in size and ease of controllability of the main body of the measuring instrument.